Today, forwarding elements commonly have control and data plane components. A forwarding element's control plane component often provides the interface for configuring the components of the data plane, while the data plane handles the forwarding of the data messages that the forwarding element receives. The data plane is often referred to as the forwarding plane. The data plane often is a custom-made application specific integrated circuit (ASIC) that includes multiple ingress pipelines, multiple egress pipelines, and a switching fabric between the ingress and egress pipelines. The control plane, on the other hand, is typically managed by one or more off-the-shelf processors, which supports the interface for locally or remotely receiving parameters for configuring the forwarding element.
Control plane processors can fail, and such failures can cause the forwarding elements to fail. Also, these processors add to the expense of the forwarding element. High-end processors not only cost more, but often require additional expensive components, such as high-end cooling systems, etc.